The United States Environmental Protection Agency has changed its stance on diesel trucks under the current administration. In contrast to previous versions of the EPA, which pursued massive penalties and even criminal fines for Clean Air Act violations, Administrator Lee Zeldin has made deregulation a major focus. He previously ordered manufacturers to stop forcing immediate limp mode on vehicles when diesel exhaust fluid runs low, and now, the EPA could take it a step further by eliminating power and speed restrictions completely.
The agency announced this change with a strongly worded press release, seeking information from top 14 manufacturers of on-road and off-road vehicles that use DEF systems. Specifically, it's requesting data regarding warranty claims, failure rates, and repairs on model years 2016, 2019, and 2023 to determine if emissions system-related issues are concentrated on one generation of equipment or spread out. Manufacturers could face additional inquiries or penalties if they don't provide the requested data within 30 days.
Historically, truck and agricultural equipment manufacturers would derate engine performance immediately when running low on DEF. Zeldin's previous edict allowed diesel pickups to run normally for 4,200 miles or 80 hours with low DEF levels before being governed to 45 mph. The EPA is now assessing whether these limitations are necessary for compliance.
Diesel truck drivers have long complained about the reliability, fuel economy, and performance issues associated with DEF and related emissions control systems. If the EPA decides to eliminate limp mode, it could significantly impact how users manage their diesel trucks' performance. The change would likely be welcomed by many drivers who currently add DEF to their trucks solely to avoid reduced performance.
However, the environmental concerns surrounding DEF usage are still a topic of debate. As the EPA considers this major overhaul, it's essential to weigh the potential benefits against the potential drawbacks. The agency's decision will have significant implications for the diesel truck industry and its users.
With the EPA seeking information from top manufacturers, it remains to be seen whether they will ultimately eliminate limp mode for diesel trucks low on DEF.